Robinson Helicopter Company R44 II N645JC accident near Dunedin, Florida

Probable cause

A partial loss of engine power for undetermined reasons.

NTSB analysis

During a local sightseeing flight, while over water with adequate fuel on-board, the pilot reported that the helicopter felt sluggish. He applied forward cyclic to accelerate and maneuvered the helicopter toward the shore. He then heard the main rotor rpm warning and also reported seeing the fuel quantity light. He entered an autorotation to the water and all occupants exited the helicopter and swam to shore. The helicopter remained submerged for more than 3 days and inspection of the helicopter and engine following recovery revealed no evidence of preimpact failure of the engine or engine accessories, including the magnetos or fuel servo. No determination was made as to the reason for the reported loss of engine power.

Text from the NTSB. Open the NTSB docket for ERA09LA421 for the full record.